Whatever happened to Las Ramblas? Once one of the most famous, admired and glamorous avenues in the world, Barcelona's tree-lined boulevard is at the centre of a fierce row over whether drunken tourists, desperate prostitutes and petty crooks have rendered it charmless, tawdry and dangerous.

Later this week the paseo where Barcelonans have paraded, partied and rioted for centuries may be the scene of yet another climactic celebration - if the city's adored football team FC Barcelona beat Manchester United in the Champions League final in Rome.

These days, however, there is a dark underside to the late-night revelry and a growing number of residents are raising their voices in complaint. Fights, vandalism and arrests marred recent celebrations to mark Barcelona's winning of both Spain's national soccer cup and the league title. But football-related violence is the least of the problems Las Ramblas faces. "I used to come here in the small hours, but now I don't dare," said Carmen Romero, one of two dozen flower sellers, whose stands have given a splash of colour to the area for centuries.

Joan de Sagarra, the writer and a recent recipient of the city's gold medal for culture, has publicly despaired over what has happened to the Las Ramblas of his youth. "When I was young, the Ramblas was a place of flowers and birds," he wrote recently, lamenting that he no longer went to have coffee, buy cigars or play the lottery. "The Ramblas of today is not my Ramblas. It is time I was able to go back and walk along it peacefully, with tranquillity and pride."

The respected La Vanguardia newspaper, for which de Sagarra writes, was withering in its judgment. "A dark boulevard where drunks impose their style, where wallets disappear and there are fights and muggings," it reported. "The sensation is of chaos, of a lost city. Barcelonans are turning their backs on it."

The mile-long Ramblas attracts some 250,000 people a day. Half are foreign and only one in five is a Barcelonan.

Early yesterday morning, a man in a Mexican sombrero with a blow-up sex doll slung over his shoulder led one of many drunken stag parties past the closed stalls of florists, bird-sellers and portrait artists. Other groups wore uniforms of pink sequinned hats, red bow ties and "I love Barcelona" T-shirts or shouted out the Liverpool football anthem You'll Never Walk Alone.

Tourists and locals swarmed up and down the boulevard's length; young Nigerian prostitutes promised quick service and low prices. Gangs of three or more girls mobbed single men, hanging on to arms and grabbing groins. "Hello, boyfriend! I want to fuck! Come on!" they said, as some men shook them off.

Critics worry that global mafias now see Barcelona's liberal reputation as a business opportunity. "We believe there is a problem with prostitution mafias and a genuine social problem of exploitation of the girls," explained La Vanguardia's assistant editor Lola García.

Some hoteliers complain that violent crime and robberies are on the increase, although they could offer only anecdotal evidence. "There have been weeks when I have had clients robbed every single day," said Joan, the receptionist at a hostel near Las Ramblas, on a street whose brothels inspired Picasso to paint the nudes in his Les Demoiselles d'Avignon a century ago. "They used to just go for bags, now they go for the person."

The authorities blame the press for the fuss, claiming newspapers are trying to oust Socialist mayor Jordi Hereu by exaggerating the problems of a neighbourhood that has always had prostitutes and petty crime.

"This press campaign is wrong," said deputy mayor Jordi Carnes. "The number of petty crimes in Las Ramblas has not gone up." He admitted, however, that the city wanted to shed a reputation as a place for drunken stag nights and hen parties. "This sort of tourism is not our target market," he said. "There are over 24 hotels in the Ramblas, with three under construction, so we are talking about a prime location."

Hoteliers, shop and bar owners fret that bad publicity will damage business. They argue that the street's success makes it a magnet for both the good and the bad. "This is a very lively street that changes hour by hour. Las Ramblas is a reflection of society as a whole and if you have 250,000 people here all sorts of things will happen," said María Dolors Álvarez, of the neighbours and traders association. "There is no law against prostitution, but we believe there is a need for debate." In its literature, however, the group compares the state of the Ramblas to the dark days of the 1970s, "when we had a similar situation, provoked by a similar economic phase".

Prostitutes have stood on the Ramblas for centuries, but were never so aggressive and stayed near the port end. The frontier was marked, more or less, by the famous Boqueria market, with its mountains of fresh fruit and colourful stalls selling everything from offal to boiled sweets. "Now we get them right here," said Carmen Romero, the flower seller.

Like other locals, Joan has voted with her feet and moved out. "We lived in the barrio for eight years. When you start seeing prostitutes doing their business in the street, it gets too much."

Even critics believe, however, that the situation is not beyond repair. "The Ramblas has always had a wild side to it and no one want to lose that completely," said Lola García. "Once you admit there is a problem, I don't see that it should be too difficult to fix. The town hall must be worried about something, as it has asked permission to install street cameras."

Although tourists routinely get into problems in and around Las Ramblas, the British consulate has not seen a recent increase in such incidents. It warns visitors, nevertheless, to be "especially vigilant".